Suntipaap Sungprakul, nickname Arjan. Poon is an experienced English lecturer who has been teaching in the various education levels in Thailand.  His previous teaching experiences prior to joining Thongsook include teaching English for the public secondary school, English tutor at the language school, and recently as an adjunct lecturer for English classes at the Faculty of Painting Sculpture and Graphic Arts (PSG) and Graduate School, Silpakorn University.

Apart from education-related work, he also tried his hand at journalism as he joined Voice TV, the leading News Station of the country as the journalist handling the scriptwriting and voice over news scoops for the international news and later, sport news. He still occasionally gives comments or interviews for the station, particularly on the education-related scoops/ news segment.